Playback Engines

A special type of receptor that has been designated to store data streams is known as an playback engine. These engines form a critical part of the elab environment.

Jane scanned the paper, nodding to herself as she read. ``Yep, yep. Makes sense.''
She dropped back in to the interaction room in her elab where she'd been talking to the other researchers, and looked at the white board again.
``I think I have an answer for you guys,'' she grinned. ``I need to think about it for a bit... see you in half an hour or so.''
She zipped a copy of the preprint off to Brian via email, and dropped off the net for a bit to drive to her real office.
Back on-line, she checked to see if Brian was around. ``Hey, grab the others, and meet me in the coffee room. I think I've got something.''
She picked up the electronic video off of her virtual desk and moved to the interaction room. She popped the video into the player and, looking over the tape contents display which appeared on her screen, she selected an experimental run from two days before.
Glancing at the images of Brian and the other scientists, she said, ``You should now be seeing the data from two days ago, when we had what we thought was a problem. See?''
They nodded, mildly puzzled.
``Now listen to what we were saying at the time, and look over the paper I just showed you. I think it all makes sense.''
They sat there for a few minutes, reliving the meeting of a few days before. Brian slowly broke into smile. ``Jane. You're amazing.''

Playback engines have many intriguing possibilities:

• They may be used to index and search the data they store. (This is known to be a very difficult problem with some types of data).
• They can be used to maintain the state of various modules, such as virtual white boards, such that the next time the module is initiated, it can have the same state as it did the last time it was used.
• They may develop into permanent repositories for important data, recallable and accessible according to the modules needs and capabilities.
• As in the example above, they can act as virtual VCRs, essentially recording a collaborative session, portions of which could be replayed at a later time.

Playback engines will need to have significant processing ability and off-line storage capability, and will most likely require high-end scalable I/O computers supporting the archiving and recall capability.

=12cm labspace.slide5.eps

The LabSpace project will provide

• A playback interface for elabs.
• A playback engine implementation that takes advantage of super computers.
• A simpler playback engine suitable for use on smaller computers.
• A method of storing data that allows one to locate and search relevant archives.